A start of packet detector comprises an input which receives start of packet information. The detector has a first stage which determines if there is a match between a respective subset of received start of packet information with a respective subset of reference start of packet information. The first stage repeats the determining for each of the subsets of received start of packet information and said respective subset of reference start of packet information. An output will provide a start of packet detected output which is dependent on the determining of the first stage.